<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<script type="text/javascript">

    function SuperType () {
        this.colors = ['red', 'orange', 'yellow', 'green']
    }
    function SubType () {
    }
    SubType.prototype = new SuperType()
    var instance = new SubType()
    instance.colors.push('cyan')
    var instance2 = new SubType()
    console.log(instance2.colors)   // 本不该有'cyan'

</script>

</body>
</html>
